1. Field of the Invention
The invention relates to a system and method for processing structured documents such as extended markup language (XML) documents.
2. Description of the Related Technology
Extensible markup language (XML) is a data description language that provides a mechanism to represent structured data in a way that retains the logical structure and interrelationship of the underlying data. In XML, data is represented as Unicode text using standardized markup syntax to express the structural information about that data. In brief, XML syntax includes tags (a string bracketed by ‘<’ and ‘>’) and attributes (syntax of the form attribute_name=“value”). The particular tags and attributes used in a document may be selected with reference to the type of data that is represented by a particular document. Moreover, an XML document may be constructed to conform to a document type declaration (DTD). A DTD is a formal description of a particular type of document. It sets forth what elements the particular type of document may contain, the structure of the elements, and the interrelationship of the elements.
While XML is human readable, XML documents, particularly those which conform to a well-known or standardized DTD, provide a convenient means of data exchange between computer programs in general, and on the Internet in particular. However, many of XML's features, as well as the use of text and the structures encoded within the text, make XML document processing processor intensive. Thus, in systems that exchange a high volume of XML data, e.g., e-commerce systems that process XML encoded security data, XML processing may tend to consume so much of a server's processing power that the amount of processing power remaining to actually apply the XML data to the relevant application may be impacted. One solution to this problem is to offload processing of XML queries to dedicated content processors that employ hardware specifically configured to process XML. However, the memory and processor requirements associated with XML processing have limited the cost effective implementation of content processing for XML queries. Thus, simpler, yet resource efficient systems and methods of processing XML documents are needed.